The turnout was larger than on 02 May, when the demonstrators tried to occupy a square in the centre of the capital before being dispersed by security forces.
At a meeting before the march, opposition leader Moustapha Ould Bedredine warned demonstrators they could expect more of the same.
“We know that the regime is again going to resort to repression, but we will resist peacefully,” he said.
A police spokesperson said that a march and rally had been authorised, but not a sit-in.
Mauritania’s opposition considers Aziz’s administration to be a military regime. The former general took part in a 2005 coup and another in 2008, which saw him seize power.
He became the president of a transitional authority, from which he resigned to contest and win 2009 elections, a move condemned as a trick by the opposition. – SAPA